Propiolic acid was directly polymerized in water with water-soluble rhodium complexes in the presence of bases such as NaOH to yield the cis-transoidal poly(propiolic acid) sodium salt (poly-1-Na) in high yields. Moreover, poly-1-Na exhibited an induced circular dichroism (ICD) in the UV-visible region in water due to the formation of a predominantly one-handed helical structure responding to the chirality of the optically active amino alcohols. The stereoregularity of the polymer decreased when the poly-1-Na was converted into the acid form, poly(propiolic acid). However, poly(propiolic acid) also showed ICDs in the UV-visible region in water in the presence of optically active amino alcohols.